A novel approach to acoustic liquid density measurements using a buffer rod based measuring cell

A new method for measuring the pressure reflection coefficient in a buffer rod configuration is presented, together with experimental results for acoustic measurements of the liquid density, based on the measurement of the liquid's acoustic impedance. The method consists of using 2 buffers enclosing the liquid in a symmetrical arrangement with a transducer fixed to each buffer. One of the transducers is used in a pulse-echo mode while the other transducer operates as a receiver. The echo amplitudes leading to the pressure reflection coefficient as found by this method possess advantages such as reduced attenuation due to a shorter liquid transmission path and reduced interference, as compared with the ABC method. Measurements with distilled water and with special density calibration oil qualities have been performed using both the new method and the ABC method and are shown for the new method to give a density span within +/- 0.15% of the reference values. A comparison of the measured densities based on both a time-domain and a l(2)-norm frequency domain integration signal processing approach is given, along with a recommendation as to how the signal processing should be performed.     

TOC会计

主要介绍TOC的基本原理、TOC会计以及产品组合。     

A method for improving joint replenishment systems with a known frequency of replenishment orders

This paper gives a simple method for improving joint replenishment systems. The method is typically applicable to the batch processing industry where a batch is blended (manufactured) and subsequently packaged into various types of containers. The objective is to package items economically. A problem has been solved for illustrating the method.     

Validation of analytical methods using a regression procedure

The evaluation and validation of analytical methods and instruments require comparison studies using sample material for testing accuracy and precision. In analytical chemistry, the commonly accepted means of analyzing data from method comparison studies is least-squares regression analysis, a model which has limitations. In this paper, the results from ordinary least-squares and many other regression approaches recommended in the literature were compared with a new regression procedure that takes into account the errors in both variables (methods). After a discussion of the properties of the regression procedure, recommendations are given for carrying out a method comparison study using informational analysis of variance. The efficiency of the regression procedure proposed is demonstrated by applying it to different data sets from published literature.     

Analysis of serial production lines: characterisation study and a new heuristic procedure for optimal buffer allocation

Buffer allocation in serial production lines is one of the important design issues, and hence it has been studied extensively in the literature. In this paper, we analyse the problem to characterise the optimal buffer allocation; specifically, we study the cases with single and multiple bottleneck stations under various experimental conditions. In addition, we develop an efficient heuristic procedure to allocate buffers in serial production lines to maximise throughput. The results of the computational experiments indicate that the proposed algorithm is very efficient in terms of both solution quality and CPU time requirements. Moreover, the characterisation study yields interesting findings that may lead to important practical implications. A comprehensive bibliography is also provided in the paper.     

GaN buffer layer growth by MOCVD using a thermodynamic non-equilibrium model

In this work, a gallium nitride (GaN) buffer layer was grown on a sapphire substrate (α-Al₂O₃) in a horizontal reactor by low pressure metal-organic chemical vapor deposition (LP-MOCVD). Trimethylgallium (TMGa) and ammonia (NH₃) were precursors of gallium and nitrogen, respectively, and hydrogen (H₂) was used as carrier gas. TMGa and NH₃ fluxes were kept constant, with flow rates of 3.36 μmole/min and 0.05 standard liter/min, respectively. The fluence of hydrogen was also kept constant with the flux rate of 4.5 standard liter/min. GaN was deposited at 550 °C and 100 mbar. According to the X-ray diffraction spectra, a buffer layer was formed with a wurtzite structure, which is the stable phase. The thermodynamic affinities were estimated as A₁ = 175.9 kJ/mole and A₂ = 62.88 kJ/mole.     

TOC在供应链管理中的应用

在介绍约束理论（TOC）一些基本观点的基础上，指出当前供应链管理中存在的问题是主要如何解决系统稳定性与灵活性之间的矛盾。文章通过运用TOC分析一些具有典型意义的供应链模型，提出解决系统稳定性与灵活性之间矛盾的方法为：采用OBR合理设置系统中的缓存。     

制约理论在管理会计中的应用一例

制约理论是当今美国和欧洲比较流行的一套管理哲理和持续改进方法。通过实际案例，根据Goldratt的5个关键步骤，找到系统的制约，利用开发和释放制约从而使系统的整体能力得以提高。     

基于约束理论的管理方法及其应用

简要系统地介绍了约束理论的基本原理，指出在企业管理的持续改进方面，其管理哲理和技术较之其他更具有普适性，并应用实例说明了这一点。     

DBR理论中瓶颈资源生产优化研究

为优化Drum-Buffer-Rope(DBR)理论中的瓶颈资源的生产安排,首先采用后推方法,利用传统的EDD或SPT法则对瓶颈资源上的负荷堆积进行推平,将推平后的订单加工顺序作为禁忌算法的初始解.同时,给出了瓶颈作业的双目标函数,即提高瓶颈产出率的同时减少订单延迟时间.在此基础上,利用禁忌优化算法,对瓶颈作业安排进行优化.算例结果充分证明了该方法的有效性.     

Divergence control of a one-level supply chain replenishment rule

We present a general control and improvement strategy for a one-level supply chain based on maintaining the divergence of the system close to zero at each time step. The online implementations as well as the results obtained are shown for a logistic chain model with an Order-Up-To policy using several demand patterns. The divergence can be obtained using the state-space volume calculated with all the state variables of the model. However, it is also possible to calculate the divergence by applying state-space reconstruction techniques using only one state variable. The results obtained with both approaches show that this strategy allows the reduction in the total cost.     

一种新的高清数字电影播放系统的高速缓存和音视频同步设计

基于FPGA和专用解码芯片结构,实现了一种符合DCI规范的2K高清数字电影播放系统.针对高清数字电影码流数据量大、传输速率高的特点,设计了一种采用乒乓结构和基于目录表的动态内存管理策略的高性能缓存系统,以及一种基于高速缓存和帧查找表的音视频同步方法,整套系统简单高效,便于VLSI硬件实现.实验结果表明,此系统可以流畅播放350Mbps码率的数字电影,并且连续播放3个小时,音视频失同步可控制在20ms之内,满足数字电影规范的要求.     

运用约束理论与作业成本进行成本核算的对比分析

在解析两种成本控制技术的原理的基础上,从目标、时间、产品成本核算的内容和资源成本的计算等方面对两种成本控制技术进行比较研究,揭示出将两种成本控制技术结合的可行性,并在最后探讨两种成本控制技术运用的结合点.     

约束理论在电磁阀生产计划中的应用

以电磁阀生产计划控制为研究对象,将约束理论引入生产系统.通过生产类型和工艺路线分析,对可能存在瓶颈工序部件的各个工序进行工时统计、生产能力负荷比较后,找出阀门生产中的瓶颈工序.运用DBR理论,对瓶颈工序建立前拉后推的生产计划编排方式,提高了瓶颈工序的生产效率,瓶颈工序的在制品堆积情况有所缓解,装配停工待料情况大大减少,电磁阀生产周期缩短了20%,使得阀门能够按时出厂.     

基于约束理论的设施规划的改进

在市场经济环境下,生产设施规划改进是企业的一项持续不断的工作。本文提出运用约束理论的基本分析步骤,结合工艺流程图分析等手段来分析生产系统的约束因素,并寻求改善和解决方案。     

Application of Theory of Constraints in an integrated poultry industry

Theory of Constraints developed by E. M. Goldratt was initially applied to production scheduling and later to various areas such as Operations, Finance and Measures, Project Management, Marketing, Sales, Managing People, Strategy and Tactics. However, these applications were in engineering industries and products. The Strategic Thinking Processes of Theory of Constraints are designed to help combat an enormous problem faced by organizations--the tendency of organizations and their management to study, construct and implement solutions in isolation. In this case study, we applied the Theory of Constraints' Strategic Thinking Process in one of the leading integrated poultry businesses in India to identify and overcome the policy constraints in the business. After overcoming the policy constraints, overwhelming improvements in throughput and Inventories were observed.     

Enhancement of interfacial catalysis in a triphase reactor using oxygen nanocarriers

Multiphase catalysis is used in many industrial processes;however,the reaction rate can be restricted by the low accessibility of gaseous reactants to the catalysts in water,especially for oxygen-dependent biocatalytic reactions.Despite the fact that solubility and diffusion rates of oxygen in many liquids(such as perfluorocarbon)are much higher than in water,multiphase reactions with a second liquid phase are still difficult to conduct,because the interaction efficiency between immiscible phases is extremely low.Herein,we report an efficient triphase biocatalytic system using oil core-silica shell oxygen nanocarriers.Such design offers the biocatalytic system an extremely large water-solid-oil triphase interfacial area and a short path required for oxygen diffusion.Moreover,the silica shell stabilizes the oil nanodroplets in water and prevents their aggregation.Using oxygen-dependent oxidase enzymatic reaction as an example,we demonstrate this efficient biocatalytic system for the oxidation of glucose,choline,lactate,and sucrose by substituting their corresponding oxidase counterparts.A rate enhancement by a factor of 10-30 is observed when the oxygen nanocarriers are introduced into reaction system.This strategy offers the opportunity to enhance the efficiency of other gaseous reactants involved in multiphase catalytic reactions.     

Determining the critical micelle concentration of a novel lipid-lowering agent, disodium ascorbyl phytostanyl phosphate (FM-VP4), using a fluorescence depolarization procedure

The objective of this study was to determine the critical micelle concentration (CMC) of a novel water-soluble plant sterol derivative (FM-VP4) using a fluorescence depolarization method. The CMC was determined by 1,6-diphenyl-1,3,5-hexatriene (DPH) fluorescence depolarization. Test solutions of various concentrations of sodium dodecylsulphate (SDS) as a positive control or FM-VP4 in water were spiked with 2 µL of 4 mM DPH in tetrahydrofuran (THF) and left overnight to equilibrate in a dark chamber. Fluorescence of each solution was measured at room temperature using a Perseptive Biosystems Cytofluor Series 4000 multi-well plate reader. Fluorescence intensity increases as DPH is incorporated into the hydrophobic core of micelles. Thus, the CMC is the value at which an abrupt increase in intensity is observed. These points were observed at 8 mM and 0.014 mM for SDS and FM-VP4, respectively. Sodium dodecylsulphate was used as a positive control and supports the validity of our results, as the literature values of SDS are reported to be between 8-8.3 mM. The CMC of FM-VP4 is reported to be 0.014 mM.     

SMILE: a novel procedure for subcellular module identification with localisation expansion

Computational clustering methods help identify functional modules in protein–protein interaction (PPI) network, in which proteins participate in the same biological pathways or specific functions. Subcellular localisation is crucial for proteins to implement biological functions and each compartment accommodates specific portions of the protein interaction structure. However, the importance of protein subcellular localisation is often neglected in the studies of module identification. In this study, the authors propose a novel procedure, subcellular module identification with localisation expansion (SMILE), to identify super modules that consist of several subcellular modules performing specific biological functions among cell compartments. These super modules identified by SMILE are more functionally diverse and have been verified to be more associated with known protein complexes and biological pathways compared with the modules identified from the global PPI networks in both the compartmentalised PPI and InWeb_InBioMap datasets. The authors’ results reveal that subcellular localisation is a principal feature of functional modules and offers important guidance in detecting biologically meaningful results.Inspec keywords: cellular biophysics, proteins, molecular biophysicsOther keywords: subcellular module identification, localisation expansion, computational clustering methods, protein‐protein interaction network, biological functions, protein interaction structure, protein subcellular localisation, subcellular modules, InWeb‐InBioMap datasets, subcellular localisation